1. Field of the Invention
This invention relates to an improved mounting arrangement for a proximity sensing device or proximity switch and more particularly to an arrangement for mounting such a proximity sensing device with respect to the outer peripheral surface of a fluid power cylinder (i.e.--a linear actuator), whereby to sense the position of an axially movable piston within the cylinder. The proximity sensing device may be, but is not necessarily, of the magnetic reed type, for example, which is actuated by the presence of a magnet carried by the piston whose position within the cylinder is being detected.
2. Description of the Prior Art
It is well known in the prior art, in a broad sense, to detect the position of an axially movable piston within a fluid cylinder by mounting a proximity sensing device or proximity switch contiguous the outer surface of the cylinder, to sense the presence of the axially movable piston at a given location within the cylinder. The proximity sensing device may operate upon the magnetic principle, as in the case of a reed switch proximity sensing device, for example, which is actuated by the presence of a magnetic member or magnet carried by the movable piston within the cylinder.
It is also known in the prior art to provide a mounting arrangement for proximity switches for use with fluid cylinders in which the mounting arrangement cooperates in some manner with one or more of the tie-rods which extend between end closures at the opposite ends of the fluid cylinder. The following United States patents are examples of patents showing such a cooperative relation:
4,071,725--Smith et al PA1 4,086,456--Bone PA1 4,230,023--Ward PA1 2,462,571--Thompson et al PA1 3,160,836--Farley PA1 3,364,361--Burger PA1 3,453,937--Haberman PA1 3,524,634--Schmidt PA1 3,691,902--Lebzelter PA1 4,161,659--Jacob PA1 4,161,685--Jacob PA1 4,176,586--Stoll et al PA1 4,316,145--Tann PA1 4,419,646--Hermle
U.S. Pat. No. 3,639,868--Gaspar et al shows a mounting arrangement for a proximity sensing device or switch which is adapted for use on fluid power cylinders of different diameters. In the patent to Gasper et al, an arm which supports a proximity sensing device such as a magnetic reed switch contiguous the outer surface of a fluid cylinder such as an air cylinder is provided with a specially contoured opposite end portion which cooperates with a slotted track mounted on the outer surface of the fluid cylinder in such manner that the arm supporting the proximity device may be adjusted to different angular positions to accommodate itself to fluid cylinders of different diameters.
The following U.S. patents also disclose various types of proximity sensing devices or the like for use with fluid cylinders or the like: